Connector



. Oct. 1, 1940'.

w. o. HAMPTON CONNECTOR Filed April 9, 1957 3 Sheets-Sheet l Oct. 1,1940. w. b. HAMPTON CONNECTOR Filed April 9, 1937 I 3 Sheets-Sheet 2INVENTOR. Wefilom 0 WWI '07? ATTORNEY.

Oct. 1, 1940. w. o. HAMPTON CONNECTOR Filed April 9, 1937 3 Sheets-Sheet5 INVENT OR.

Weldon 0, 7/66 ATTORNEY.

Patented Oct. 1, 1940 UNITED STATES PATENT orrlcs Delta Star ElectricCompany,

corporation of Illinois Chicago, Ill., :1.

Application April 9, 1937, Serial No. 135,963

3 Claims.

This invention relates to connectors in general and more particularly tosuch connectors as are used on high voltage or high current carryingelectrical connections where space is limited. The

invention is, however, not limited to such connectors, as in itsbroadest aspects it is capable of general application, it beingapplicable wherever a conductor, or pipe, or rod is to be joined tosomething else and wherein there is likely to be a pull exerted on theconductor tending to pull it out, and it is desired that the connectorserve to grip the conductor firmly against such withdrawal.

In the making of electrical connections, where the current flow is ofconsiderable magnitude, it is desirable that the parts being connectedhave an appreciable contacting area at highpressure, since up to certainlimits the resistance, and therefore the amount of heat generated,varies as an inverse function of the pressure and area of contact. Inthose connectors where provision is made for an appreciable area ofcontact between engaging surfaces, it is a common experience to findthat the parts engage one another at a few points, or along a few lineswhere practically all of the pressure appears to be concentrated, theremaining portion of the connector that is intended to bear against theconductor being practically useless for current carrying purposes. Thusthe current flow is concentrated primarily at the points of highpressure, resulting in a large and concentrated heat generation.

Also, in such arrangements the conductor is not held in the connectionwith sufiicient eilective grip to prevent the conductor from beingpulled out of the connector. It is anpbject of the present invention toovercome the above difficulties.

1 accomplish this result by providing a connector which is soconstructed and arranged that the pressure of engagement between theconnector and the conductor is fairly evenly distributed along theentire length of the end of the conductor that is being gripped by theconnector.

This is accomplished by making the conductor receiving opening of theconnector slightly tapered away from the conductor along its length ofengagement with the conductor so that as the connector is clampedagainst the conductor the portion of the connection remote from theclamp- 50 mg means first engages the conductor and as the clamping meansis progressively tightened the connector is flexed to bring itprogressively into pressure engagement with more and more of the end ofthe conductor. The taper of the con- 55 nector is such that upon flexingof the same the pressure of engagement between the connector and theconductor is fairly even throughout the engaged length of the conductorend. The connector is provided with a series of teeth that bite into theconductor, the pressure of the respec- 5 tive teeth being substantiallyuniform so that the current flow between the connector and the conductorwill be substantially equally distributed at the respective teeth.

It is a further object of the present invention 10 to provide aconnector having a smooth exterior surface free of outward projectionsand free of sharp corners at points of electrical stress. By suchconstruction I reduce the minimum distance that must be allowed betweenadjacent l5 connectors on line conductors at different potentials. Also,by reason of the smooth exterior surface-the connector may readily betaped over with cable insulation without the danger of leaving voidsunder the tape. Voids in taped insula- 20 tion are highly objectionablesince there may be such an increase in the electrical stress at thevoids as to result in corona formation and consequent rapiddeterioration of the tape.

It is another object of the present invention 25 to provide a connectorwhich will firmly grip the conductor to which the circuit is beingextended and securely hold the conductor from being pulled out by anyforces which might reasonably be encountered tending to pull theconductor out. 30 This result is accomplished by constructing theconnector in such a manner that it will firmly grip the conductor for anappreciable distance along the end of the conductor and providing aseries of teeth in the connector which will bite 5 into the conductor. Iestablish a plurality of rings of high pressure contact between theconnector and the conductor, each ring comprising a tooth extendingaround the periphery of the conductor engaging portion of the connector,the 40 connector being clamped to the conductor with sui'licientpressure to cause the connector teeth.

or rings to penetrate the conductor.

It is a still further object of the present invention to so constructand locate the teeth on the connector that the respective teeth "willexert substantially uniform pressureon the conductor. By thisarrangement I obtain a connection having a minimum resistance and amaximum anchoring grip.

It is a still further object of the present invention to provide aconnector of the character above set forth in which the parts may bedrawn together by tightening a single bolt, so that only one hand needbe used to manipulate the wrench during tightening operations. By thisarrangement the other hand is free so that the operator can amplysupport himself. This is of importance because frequently connectionsare in such a location that the operator must use one hand to maintainhimself against falling.

The attainment of the-above and further objects of the present inventionwill be apparent from the following specification taken in conjunctionwith the accompanying drawings forming a part thereof.

In the drawings:

Figure 1 is a longitudinal sectional view through the connection beforetightening of the clamping bolt;

Figure 2 is an enlarged sectional view through one of the connectorsegments;

Figure 3 is a bottom view of a connector seg ment;

Figure 4 is a sectional view taken along the line 4-4 of Figure 2 andlooking in the direction of the arrows;

Figure 5 isan end view of the connector segment of Figure 3;

Figure 6 is a longitudinal sectional view through the completedconnection;

Figure '7 is a plan view of the connection of Figure 6;

Figure 8 is a plan view of a connector of a modified construction;

Figure 9 is a side view of the structure of Figure 8, a portion of theconnector being shown in section for illustrative purposes;

Figure 10 is a plan view of another modification of a connectorconstructed in accordance with the teachings of the present invention;

Figure 11 is a side view in partial section of the structure of Figure10;

Figure 12 is a side view of still another form of connector; and

Figure 13 is a Figure 12.

Reference may now be had more particularly to Figures 1 to 7 inclusive.Those figures illustrate an electrical connection between the line I andthe conductor 2, and illustrate further the construction of theconnector that effects the connection.

The line i may comprise a stranded, solid, or tubular conductor 2, orany other continuous conductor to which an electrical connection is tobe made.

The connector includes two massive cast bronze connector segments 3 and4 secured together by a single bolt 5 which passes freely through anoversized opening in the segment 3 and is threaded into the segment 4.The segment 3 is provided with a circular depression or cavity 8 at thetop thereof for receiving all or a major portion of the head of the bolt5, as may be seen from Figures 1, 6 and '7. The head of the bolt restson a curved surface 9 of the connector segment 3, the surface beingcurved to permit a slight rolling of the head of the bolt with respectto the connector segment as the two segments are tightened by the boltand flexed towards one another in a manner to be set forth more fully asthis description proceeds. To facilitate this action the bolt hole I inthe segment 3 for receiving the shank of the bolt 5 is made preferablyslightly conical as is shown in somewhat exaggerated form forillustrative purposes.

Each connector segment is provided with an almost semi-cylindrical boreI 2 at one end, adapted to fit over the conductor I. The surface l2 planview of the connector of is a portion of a cylindrical surface havingits center at l3 (Fig. 2), which, in one construction, is approximatelyfrom the plane of the edge surface I 4 of the connector segment. Eachconnector segment is provided with a bore or cavity I6 at approximatelyright angles to the bore formed by the cylindrical surface I2.

The bore or cavity l6 has a plurality of teeth I! for biting into theconductor 2. Each tooth extends around the periphery of the bore, and ispreferably shaped on an arc of a circle, as may be seen from Figure 4,but the teeth are of varying depths from the edge surface ll of theconnector segment.

In Figure 2 I have shown a center line 20 which is the line for thecenters of the grooves or teeth IT. This line is at a slight angle tothe surface l4, so that at the inner end 2| of the connector the groovesextend further from the surface H than at the outer end 23', by a smallamount. In one connector which I have made and used, this amount isapproximately one thirty-second of an inch. When the two connectorsegments are placed around a conductor in the manner illustrated inFigure 1, the teeth at the end 22 of the two connectors first engage theconductor 2, while the teeth closer to the bolt, as at 2|, do not engagethe conductor. The bolt 5 is tightened to firmly clamp the segmentsagainst the conductors, the tightening being continued to causedeformation or flexing of the connector segments towards one another atthe bolt 5 and thus bring the teeth progressively into high pressureengagement with the conductor 2 until the teeth at the end 2| firmlygrip the conductor 2. Upon tightening of the bolt 5, the conductor 2 isbeing compressed but it cannot expand radially due to the fact that thewidth of the bore lt'at the surface II is approximately uniformthroughout the length of the bore, as may be seen from Figure 3. Anyyielding of the conductor upon clamping of the segments together resultsin a pushing of the metal of the conductor progressively to the left, asseen in Figures 1 and 6, namely, into the connector rather thanoutwardly thereof. As a result, all of the teeth II firmly grip theconductor 2 and positively lock it against withdrawal by an outward pullon that conductor. Also, due to the difference in the depth of the boreit, gradually increasing from the end 23 of the bore towards the bolt 5,a tightening of the bolt and consequent deflection of the metal of theconnector segment causes all of the teeth of the connector to grip theconductor substantially uniformly. In the absence of such a taper of thebore l6, a tightening of the bolt 5 would cause the teeth I! grip theconductor tightly while the teeth at the end 23 of the conductor wouldbear against the conductor loosely, and would therefore be of onlysmall, if any, effect both as to' current conducting function and as togripping the conductor against pull-out.

When the connector segments are clamped together to grip the conductor2, they also firmly grip the conductor I and establish intimate contactwith that conductor. During the tightening action by the bolt 5 anddeflection of the connector 3, the head of the bolt 5 may roll slightlyon the curved surface 9, thus avoiding any binding action on the bolt.

It is to be noted that the exterior surfaces of the connector segmentsare smooth and are free of any appreciable outward projections. Thisreduces the possibilities of streamer or corona formation andfacilitates the application of insulatadjacent the bolt 5 to ing tapearound the connector, thereby permitting the use of the connector inrather crowded spaces Where the matter of obtaining adequate electricalclearance presents a problem. Also, by reason of the smooth exterior ofthe connector, it is easy to wind insulating tape around the sameWithout trapping air or otherwise forming voids between layers ofinsulating tape. The presence of voids between layers of insulating tapeis highly objectionable. The electrical stresses are increased at thevoids, resulting frequently in the formation of corona and consequentrapid deterioration of the insulating tape.

In Figures 6 and 7, the wound tape is indicated at 28, said tape beingwound around the connector segments and over the cable insulation 29.The winding of insulating tape or insulating cords 30, suitablyimpregnated with insulating compound, fills the spaces that wouldotherwise be present between the end of the insulation 29 on theconductor 2 andv the ends of the connector segments, this layer ofinsulation 30 forming a smooth, continuous connecting surface betweenthe connector segments and the insulation 29 on the conductor.

The head of the bolt lies practically entirely within the pocket 8formed within the connector segment 3. Since the head of the bolt is atexactly the same potential as that of the surrounding wall of the pocket8, this space is electrically dead and therefore the presence of an airpocket at this space is not objectionable. Since the head of the boltdoes not project appreciably beyond the surface of the connector, if itprojects therefrom at all, the bolt head does not interfere with thewinding of the tape around the connector. The connector 5 is preferablymade of bronze or other non-ferrous metal. Such a bolt holds its gripfirmly and does not tend to become loosened.

Reference may now be had more particularly to Figures 8 and 9, wherein Ishow the principles of the present invention embodied in anotherconnector structure. In this construction, the two cast bronze connectorsegments are indicated at 35 and 36, the two segments being providedwith a bore for receiving the conductor 2, which bore is of aconstruction such as was previously described in connection with Figures1 to 7 inclusive. The connector segment 36 is provided with asemi-cylindrical depression or transverse groove 38, corresponding tothe groove |2 of Figure 1, which fits over a correspondingsemi-cylindrical projection 39 formed integral with the segment 35. Whenthe bolt 5 is tightened to draw the segments together, the segment 36 isflexed into firm gripping relationship to the conductor 2 in the samemanner as do the connector segments 3 and 4, previously described. Theportions of the connector segments to the left of the bolt, as seen inFigure 9, are deflected, or distorted from their normal position, theamount of distortion being maximum at the bolt 5, and minimum at the endremote from the bolt 5, namely, at the outermost ends of the segments.During this action the segment 36 rocks about the projection 39. Becauseof the taper of the conductor-receiving grooves, orportion I6,previously described, the teeth on the segments 353B firmly grip theconductor 2 with a uniform pressure in the manner previously explained.The segment 35 is provided with a terminal lug 40, of any desiredconstruction, for receiving a terminal lug at the end of a conductor towhich a connection is to be made, or whereby the connector may be boltedto a terminal of a switch or other structure to.establish electrical andmechanical connections between the terminals. The connector segments3536 are of the smooth exterior as in the case of the connector shown inFigure 1, so that the segments may be taped with insulating tape, in themanner explained in connection with Figure 1.

In Figures and 11 there is shown still another connector forestablishing connections between two conductors. This connector includestwo cast metal segments 5||5I of bronze or other suitable material. Theconnector segment 50 is provided with a bore 52, into which the baredend of a conductor 53 is fitted, being soldered in place in the usualmanner, to provide firm mechanical and electrical connectionsbetween theconductor 53 and the connector segment 5!). At its opposite end, thesegment 50 has an extension 54 terminating in a top surface 55 in whicha conductor-receiving toothed groove l6, of a construction similar tothat of the connector of Figure 1, is formed. The conductor segment 5|,has a similarly formed toothed groove Hi, the teeth of the grooves|6--|6 being of a construction and varying depth, as in the connectorsegment, illustrated in Figures 1 to 7. The connector segment 5| isprovided with a boltreceiving bore 51 for receiving the bolt 5 whichthreads into a threaded portion in the connector segment 50 for securingthe two connector seg ments together. The segment 5| is provided,

at its lower surface, with a projecting nose 59,

which rests on the surface 55 of the projecting portion 54. -When thebolt 5 is tightened, the connector segment 5| and the projecting portion54 of the segment 50 are flexed towards one another, the segment 5|rocking about the curved portion 59. Here, as in the previousconstruction, the maximum deflection of the two segments is produced atthe bolt, and the minimum deflection at the point furthest away from thebolt. Because of the varying depths of the teeth H, as previouslydescribed, each of the teeth from the left hand side of the connectorbore IE, to,

the right hand side thereof, is progressively brought into grippingrelationship with the end of the conductor 60. After a connection isestablished, the connector may be taped in the manner described inFigure 1.

While I have shown, in Figures 10 and 11, an arrangement wherein theconnector segment 50 is provided'with a bore 52 for receiving theconductor'53, and while the connector of Figure 9 is shown with a lugfor receiving electrical connections, itis to be understood that theconnector of Figures 10 and 11 may be provided with a lug instead of thebore 52, and conversely, the connector of Figure 9 may be provided witha bore such as the bore 52 instead of the lug 40, or any other means maybe providedvfor establishing connections with the connector segments atthe right hand side of the connectors of Figures 8 and 9, or 10 and 11,as desired.

Reference may now be had more particularly to Figures 12 and 13. Theconnector shown in these figures employs two bolts instead of one. Thisconnector is of the same shape in transverse section as the connector ofFigures 1 to 7.

It is provided, at each end, with toothed grooves |6|6 of a constructionsuch as was described in connection with the groove N5 of the connectorof establishing firm electrical and mechanical connections between theconductors 66 and 68. It is to be noted that here, as in previousconstructions, the connector segments are of a smooth exterior surface,free of any projections, and that the heads of the bolts lie in thepockets in the connector segments so that the space between the boltheads and the adjacent connector surface at the bolt head receivingpocket is electrically dead. Because of the smooth exterior surfaces, itis a very simple matter to wind insulating tape around the connectorsegment after the segments have been bolted together into firm grippingrelationship to a pair of conductors.

In each of the constructions above described .the conductor is grippedfirmly along the entire length of the end thereof thatis within theconnector. The pressure of the respective longitudinally spaced teethagainst the conductor are substantially uniform. This results in aminimum electrical resistance loss at the connector, and in a firmgripping of the connector against withdrawal by an outward pull. Whilethe connector segments are particularly adapted for anchoring the end ofa conductor and establishing electrical connections thereto, it is to beunderstood that the connector is not limited to such use. It may beused, for instance, for merely anchoring the end of a conductor or theend of a pipe or for joining two pipes or rods, even though there is noquestion of establishing electrical connections between the pipes orrods that are joined. The connector of the present invention may be usedwherever it is desired to firmly anchor the end of a pipe, rod or wire.

From the above description'it is apparent that the connector of thepresent invention comprises essentially two massive cast metal segmentswhich are, in effect, springs so that one or both of the segments may bedistorted, or flexed, from its normal position by the application of avery great force thereto, but preferably within the elastic limit of themetal, and upon release of the applied force the segments resume theiroriginal shapes. The force applied to flex the segments is the forcethat exerts the clamping pressure between the segments and the connectedconductor or conductors. Furthermore, it is to be .noted that when thesegments are in their fully clamped position, as illustrated in Figure6, the adjacent surfaces Ml4 of the two segments are still spaced apart.By reason of this spacing the operator is assured that all the pressureexerted by the bolt is transmitted to the conductor or conductorsbetween the segments. If the surfaces I4-|4 were in abutment then theoperator, upon tightening of the bolt 5 to the desired degree oftension, would not know Whether the pressure exerted by the bolt isexerted on the conductors or on the faces l4-l4. Also, by reason of thecurved surface 9, the segment 3 can roll or rock with respect to thehead of the. bolt 5 as the two segments are being flexed with respect toone another. This arrangement precludes jamming of the bolt head withrespect to the connector. It is known that the electrical resistance ata joint between two contacting metal members varies inversely as thepressure between the members, within predetermined limits. In the caseof a point or line contact an increase in pressure results in a decreasein resistance until a predetermined pressure is reached, whereupon anyfurther increase in pressure produces only a negligible, if any, changein resistance. For this reason it'is important to have a number of teethI! on the connector segments, and to arrange the segment structure sothat the pressure is distributed between all the teeth with more or lessuniformity. Any concentration of pressure at one tooth with acorresponding diminution of pressure at one or more other teeth willreduce the total current carrying capacity of the connector, or increasethe heating of the same, since the resistance is appreciably increasedat those teeth where the pressure is reduced, and is not correspondinglydecreased at that tooth where the pressure is increased. By reason ofthe original taper of the axes of the segments 3 and 4, as illustratedby the inclination of the center line 20 of Figure 2, I assure aconstruction wherein the pressure exerted by the teeth onv the conductor2 will be substantially uniform. Also, as the connector segments aredrawn together the metal of the stranded conductor 2 is forcedprogressively inwardly from the end of the connector towards the centerthereof, rather than in the reverse direction. By this arrangement Iassure a tight gripping of the conductor so that there is no reasonabledanger that the conductor 2 may be pulled out of the connector by forceslikely to be exerted upon the conductor 2. The elastic bite of theconnector segments against the conductor 2 assures a tight gripping ofthe conductor. Also, it is to be noted that the grooves formed by theteeth I1 are tapered in such a manner as to resist an outer pull on theconductor 2 when the segments are clamped tightly against the conductor.This is so by reason of the fact that the slots formed by the teeth IIare wedge-shaped in cross section, with the right hand side of eachslot, as seen in Figure 6, substantially vertical. This facilitates theanchoring of the conductor, or pipe, or tube, or rod, that may be heldby the connector segments.

In Figures 8 to 13 I have omitted the conical shape or taper on the boltreceiving bore [0 or 51. In these constructions the bore is slightlymore oversized than in Figure 1, thus avoiding binding of the connectorsegments against the shank of the bolt as the segments are clampedtogether. Either the conical shape of the bolt receiving bore, or anoversize bore may be provided, as. desired, in any of the embodimentshere illustrated.

In compliance with the patent statutes I have here shown and described afew preferred embodiments of my invention. It is, however, to beunderstood that the invention is not limited to the preciseconstructions here shown, the same being merely illustrative of theprinciples of the invention. What I consider new and desire to secure byLetters Patent is:

1. A spring metal connector clamp comprising two segments havingcooperating grooves for receiving a conductor, a conductor in saidgrooves, the axes of the cooperating grooves in the two segmentsdiverging from one another from the ends of the segments towards thecenter of the segments, means for clamping the two segments together toexert a high pressure upon the conductor in the grooves of the segments,said segments being so proportioned in relation to the size of theconductor that the grooved part of at least one of the segments firstcontacts the conductor at the end of the segment remote from theclamping means the segments being sufiiciently elastic to allow relativedeflection thereof by the clamping means to bring the axes of the twogrooves into parallelism, said clamping means comprising a boltextending into a countersunk hole in one of the segments so that thebolt head is substantially entirely within the countersunk hole, theseating surface forvthe head of the bolt in the countersunk hole beingcurved to permit rolling of the adjacent segment with respect toclamping the two segments together to grip the conductor in thecooperating grooves, the conductor-engaging surface of at least one ofthe segments being tapered to grip the conductor first at the end of thesegment remote from the bolt and said last mentioned segment beingflexed by the bolt to straighten the tapered surface whereby the taperedconductor-engaging surface is progressively brought intopressuregripping engagement with more and more of the conductor length,the head of the bolt resting substantially entirely within thecountersunk hole and the outer surfaces of the assembled segments beingsmooth and free of sharp corners and projections, to inhibit coronaformation and facilitate the application of insulating tape thereto. anda wrapping of insulating tape enclosing said connection.

3. An electric connection including a connector comprising two separateconnector segments adapted to be clamped together with adjacent facesseparated by and pressing against a conductor, said adjacent faceshaving conductorreceiving grooves opposite one another to receive theend of a conductor between the segments so that a conductor may lie inthe grooves of both segments, said grooves having teeth at the conductorengaging surfaces thereof, bolt means for drawing the two segmentstogether to force the teeth into pressure egagement with the conductorin said grooves, said bolt means lying substantially entirely within theconnector segments and including a non-circular part for facilitatingturning of the bolt means, said connector having a socket within whichsaid non-circular part lies in substantially its entirety, saidnon-circular part having a seating surface bearing against the inside ofthe socket as an opposite seating surface, said opposite seating surfacebeing convex so that the peripherally outermost edge of the seatingsurface on the bolt means is out of high pressure engagement with theopposite seating surface when the bolt means is tightened to bring thesegments into high pressure engagement with a conductor in the grooves.

WELDON O. HANIPTON.

